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The cultivation of sunflower (Helianthus annuus L.) as a cut flower stands out in floriculture due to its aesthetic beauty and commercial value. Understanding how cut sunflower genotypes adapt to different edaphoclimatic regions and management practices is essential to optimize flower quality and productivity. This study aimed to evaluate the effect of plant density and location on the development, growth, and quality of cut sunflower in tropical and subtropical environments. Plant densities of 10, 20, 30, 40, and 50 plants/m2 were evaluated in tropical climate and subtropical climate using a randomized block design in a factorial scheme. Results showed significant differences between locations for plant height, capitulum and stem diameter, final number of leaves, leaf area, leaf area index, phyllochron, and the developmental cycle. Plant density significantly influenced these variables except for plant height and developmental cycle. The interaction between location and plant density was significant only for capitulum diameter and final leaf number. The findings indicate that both planting density and location significantly influence the developmental cycle of cut sunflowers, with lower densities favoring more robust plants at harvest. A density of 30 plants/m2 is recommended for efficient space use without significantly compromising floral stem quality. All produced stems are marketable, suggesting that adjusting planting density can optimize production without compromising quality, adapting to specific regional conditions. [ABSTRACT FROM AUTHOR]

Kale (Brassica oleracea var. Achepala) is a leaf vegetable plants from the Brassica family that has high potential to develop. The use of nutrients in hydroponic cultivation has important role to fulfil the nutrient needs of curly kale plants. The presence of nitrogen is important for kale in growth and crop result. Cultivation with floating raft system needs to focus into the ideal population to get an optimal growth rate. This study aimed to obtain the correct amount of nitrogen concentration and plant population on the growth and yield of curly kale with floating raft hydroponic system. This research conducted in the Green house experimental field of Agriculture Faculty, University of Brawijaya on August 2022 to November 2022. The research using Factorial Randomized Block Design with 2 factors and 3 replication. The first factor is nitrogen concentration of hydroponic nutrients, and the second factor is plant population. The result implies that Nitrogen concentration 2M with 4 plants population given higher EC value. 1,5M nitrogen concentration on 4 population plants and 2M nitrogen concentration on 6 plants population given the higher leaf area. Combination of nitrogen concentration of 1M and 2M and 8 plant population gives higher fresh total weight per container. 2 M nitrogen concentration given higher number of leaves and EC value in the media, but given shorter result the root length of curly kale than nitrogen concentration of 0,5M. 8 plants population gives lower number of leaves and root length than 4 curly kale plants population. [ABSTRACT FROM AUTHOR]

Planting geometry is one of the most important management practices that determine plant growth and yield of corn. The effects of eight planting geometries (35 × 23 cm, 40 × 21 cm, 45 × 19 cm, 50 × 18 cm, 55 × 17 cm, 60 × 16 cm, 65 × 15 cm, 70 × 15 cm) on plant growth and yields of three sweet corn hybrids (Argos F1, Challenger F1, Khan F1) were investigated under Erzurum, Türkiye conditions in 2022 and 2023 years. Variance analysis of the main factors shows a highly significant effect on whole traits but in two-way interactions some of the traits were significant and in the three-way interactions, it was insignificant. As an average of years, the number of plants per hectare at the harvest varied between 92,307 (35 × 23 cm) and 120,444 (70 × 15 cm) according to the planting geometries. The highest marketable ear number per hectare (107,456), marketable ear yield (24,887 kg ha−1), and fresh kernel yield (19,493 kg ha−1) were obtained from the 40 × 21 cm planting geometry. The results showed that the variety Khan F1 grown at 40 × 21 cm planting geometry obtained the highest marketable ear number (112,472), marketable ear yield (29,788 kg ha−1), and fresh kernel yield (22,432 kg ha−1). The plant density was positively correlated with marketable ear number (r = 0.904 **), marketable ear yield (r = 0.853 **), and fresh kernel yield (r = 0.801 **). The differences among the varieties were significant for the studied traits, except for plant density and kernel number per ear. In conclusion, the variety Khan F1 should be grown at the 40 × 21 cm planting geometry to maximize yields under study area conditions without water and nutrient limitations. [ABSTRACT FROM AUTHOR]

Plant responses to multiple environmental conditions in the habitat are characterized by intra-species variety. Ferula assa-foetida L. is a native medical plant in Iran, which has a wide range of therapeutic and pharmacological properties. The objective of the current study was to identify changes in phenolic content, antioxidant capacity and essential oil (EO) composition in different tissues (leaf, flower and fruit) of three populations of F. assa-foetida L. (Sarbisheh, Nehbandan, located in South Khorasan province of Iran). The results showed that total phenolic content (TPC), total flavonoid content (TFC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity in the leaves of Sarbisheh were higher than in other treatments. The amount of TPC, TFC and DPPH scavenging activity in leaves was higher than in other tissues in the Sarbisheh population, increasing by 31 and 70%, 41 and 20%, 8 and 13%, respectively, over that of flowers and fruits. The main EO compounds of leaves were α -pinene (11.86–13.56%), β -pinene (6.80–7.99%), bornyl acetate (15.80–17.33%). The main EO constitutes of flowers were Z-propenyl-sec-butyldisulfide (10.12–12.4%), eco-fenchyl acetate (10.87–12.4%), myrcisticin (13.43–15.87%) and α -bisabolol (11.23–13.76%). The primary compounds of fruit EO were β -pinene (9.32–11.26%), (Z)-1-propenyl sec butyldisulf (17.54–18.87%) and (E)-1-propenyl sec butyldisulf (28.32–30.02%). The agglomerative hierarchical clustering showed that three distinguished clusters were identified for population, where Nehbandan and Qaen had the higher similarity and Sarbisheh completely differed from the two ones. Different plant tissues contain varying types of chemicals, with leaves exhibiting higher levels of phenolic content and antioxidant capacity. This characteristic can be beneficial for industries such as food and pharmaceuticals. [ABSTRACT FROM AUTHOR]

Common bean is an important crop due to its high nutritional value. However, its production in Ecuador has decreased due to biotic and abiotic factors. Understanding the mechanisms that determine the yield components of this crop is essential to establish strategies that allow increasing the yield. In this study, the plant density was modified to evaluate its impact on yield and its two main components, the grain number and grain weight under field conditions in an Andean region of Ecuador. Two experiments planted on different dates were performed, where two planting densities 4 and 11 plants m􀀀2 were evaluated. The effect of the treatments was studied on the length of the period, from emergence to anthesis, the number of full and empty pods, grain number, 100 grain weight and grain yield. The results indicate that the plant density has a significant effect (p<0.05) on the yield, reaching an average of 257.15 g m􀀀2 in high density, and 151.45 g m􀀀2 in low density. The yield main components showed a different response to plant density modification; the grain number exhibited a strong variability and was positively associated with final grain yield (p<0.05) while the grain weight was not affected. [ABSTRACT FROM AUTHOR]

This study assessed the optimal nitrogen (N) fertilizer rate and planting density for the well-adapted upland rice cultivar NERICA_4 on the Fogera Plain. The primary objective was to evaluate the effects of varied planting densities and N-fertilizer rates on upland rice yield and other agronomic parameters. A two-year field study (2020 and 2021) was conducted at the Fogera Rice Research Field Station, testing nine plant densities (75, 87, and 98; 72, 82, and 91; 70, 79, and 89 plants per m2 and two N rates (115 and 138 kg N ha−1). The Crop Simulation Model Crop Environment Resource Synthesis (CSM-CERES-Rice) within the Decision Support System for Agrotechnology Transfer (DSSAT) framework was calibrated and validated using site-specific weather, soil, crop, and agronomic management data from the experiment. Results on the subsequent RMSE, RMSEn, and d index values during the calibration phase were 0.074 t ha−1, 1.82 %, and 0.86 of grain yield; 0.307 t ha−1, 3.36 %, and 0.87 of by-product yield; 0.489 t ha−1, 3.74 %, and 0.79 of top dry biomass yield; and 0.28, 8.24 %, and 0.63 of leaf area index values, respectively. Whereas results on the corresponding RMSE, RMSEn, and d index values during the evaluation phase were: 0.58 t ha−1, 1.33 %, and 0.90 of grain yield; 0.69 t ha−1, 0.58 %, and 0.99 of by-product yield; 0.678 t ha−1, 4.36 %, and 0.67 of top dry biomass yield; and 0.75, 13.92 %, and 0.74 of leaf area index, respectively. The findings of the long-term simulation showed that a 23 % increase in grain yield was achieved with 138 kg N ha−1 and 87 plants per m2 of planting density, as compared to 115 kg N ha−1 and 75 plants per m2 of plant density. The recommended optimum plant density and N fertilizer rate were 138 kg N ha−1 with PD2 of plant density for upland rice production in the Fogera Plain.

The cultivation of sunflower (Helianthus annuus L.) as a cut flower stands out in floriculture due to its aesthetic beauty and commercial value. Understanding how cut sunflower genotypes adapt to different edaphoclimatic regions and management practices is essential to optimize flower quality and productivity. This study aimed to evaluate the effect of plant density and location on the development, growth, and quality of cut sunflower in tropical and subtropical environments. Plant densities of 10, 20, 30, 40, and 50 plants/m2 were evaluated in tropical climate and subtropical climate using a randomized block design in a factorial scheme. Results showed significant differences between locations for plant height, capitulum and stem diameter, final number of leaves, leaf area, leaf area index, phyllochron, and the developmental cycle. Plant density significantly influenced these variables except for plant height and developmental cycle. The interaction between location and plant density was significant only for capitulum diameter and final leaf number. The findings indicate that both planting density and location significantly influence the developmental cycle of cut sunflowers, with lower densities favoring more robust plants at harvest. A density of 30 plants/m2 is recommended for efficient space use without significantly compromising floral stem quality. All produced stems are marketable, suggesting that adjusting planting density can optimize production without compromising quality, adapting to specific regional conditions.

Planting geometry is one of the most important management practices that determine plant growth and yield of corn. The effects of eight planting geometries (35 × 23 cm, 40 × 21 cm, 45 × 19 cm, 50 × 18 cm, 55 × 17 cm, 60 × 16 cm, 65 × 15 cm, 70 × 15 cm) on plant growth and yields of three sweet corn hybrids (Argos F1, Challenger F1, Khan F1) were investigated under Erzurum, Türkiye conditions in 2022 and 2023 years. Variance analysis of the main factors shows a highly significant effect on whole traits but in two-way interactions some of the traits were significant and in the three-way interactions, it was insignificant. As an average of years, the number of plants per hectare at the harvest varied between 92,307 (35 × 23 cm) and 120,444 (70 × 15 cm) according to the planting geometries. The highest marketable ear number per hectare (107,456), marketable ear yield (24,887 kg ha−1), and fresh kernel yield (19,493 kg ha−1) were obtained from the 40 × 21 cm planting geometry. The results showed that the variety Khan F1 grown at 40 × 21 cm planting geometry obtained the highest marketable ear number (112,472), marketable ear yield (29,788 kg ha−1), and fresh kernel yield (22,432 kg ha−1). The plant density was positively correlated with marketable ear number (r = 0.904 **), marketable ear yield (r = 0.853 **), and fresh kernel yield (r = 0.801 **). The differences among the varieties were significant for the studied traits, except for plant density and kernel number per ear. In conclusion, the variety Khan F1 should be grown at the 40 × 21 cm planting geometry to maximize yields under study area conditions without water and nutrient limitations.

The aim of this study was to evaluate the agronomic performance of sorghum grown in different combinations of row spacing and plant density, as well as possible interferences on silage quality. No other study dedicated to identifying the interference of plant spatial arrangement on the cultivation of silage material has been developed in the productive context of the Amazon Biome, making it necessary to understand the behavior of the studied factors. The treatments were arranged in a split-plot scheme: the plots corresponded to three row spacings (0.45 m, 0.60 m, and 0.75 m) and subplots at four densities (105,000, 120,000, 135,000, and 150,000 plants ha−1). The agronomic and productivity characteristics of sorghum and the fermentative and bromatological characteristics of forage and silage were evaluated. The sorghum plants showed an increase in plant height and green and dry mass yield when using higher densities (p < 0.05). For the culm diameter variable, an isolated effect of the factors was observed, with reduced diameter when grown closer to inter-row spacing or using higher plant densities. No effect of the factors was found (p > 0.05) for morphological plant components. In silage, wider spacing promoted higher dry matter content. Regarding crude protein in the silage, higher percentages were obtained at closer spacing and higher plant density. The sorghum growing in dense conditions is indicated, given the positive performance in productivity and bromatological composition. [ABSTRACT FROM AUTHOR]

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Low density sugarcane plantation (LDSP) has been implemented by some sugarcane producers in Brazil, aiming to save seeds and operational costs. The study was carried out in the municipality of Areia, Paraíba, Brazil. Five planting densities were used, varying from 5 to 25 m-2 of buds arranged in randomized blocks, with four replications. Data were measured annually over three cultivation cycles (2017 to 2020), during which the field was fertilized with NPK and the harvests were carried out manually without prior burning. The lower planting density presents higher productivity only in the cane plant (101.03 t ha-1) due to the higher plant height (2.37 m) and the higher number of stalks (11 stalks m-2), suggesting that these variables are due to the greater availability of light, water and photosynthate. However, there is a drastic reduction in sugarcane yield for this lower population in the 2nd ratoon by up to 65.62%, which is correlated with number of stalks per meter. We demonstrate the agronomic viability of LDSP in the population of 10 buds m-2 in relation to conventional planting of sugarcane until the 2nd ratoon. Data are important for future studies to present additional considerations for other production factors, such as the effects of mechanized harvesting and the management of nutrients and water, assessing the sustainability of this large-scale planting system.

Tef is a small-seeded staple crop endemic to Ethiopia. However, its yield is low, constrained partly due to improper agronomic practices and lodging. Thus, during the 2019–2020 cropping season, a field experiment was carried out at Reef Tokko Taanne Hamilee in Hababo Guduru district, Western Ethiopia to examine the effects of seed rate and inter-row spacing on growth, phenology, yield, and lodging severity of tef crop. Three levels of seed rates (10, 15, and 20 kg ha−1) and three styles of row spacing (10, 15, and 20 cm) were combined in a factorial combination in a randomized block design with three replications.Tef variety called ‘Guduru’ was used as planting material. The result showed that seed rate and inter-row spacing had significant (p

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Popcorn (Zea mays L. everta) is a specialty crop with a higher aggregate economic value than that of common maize. In Brazil, national literature is still incipient and contradictory in terms of plant population management and water requirements. Furthermore, the interaction between these factors has not been reported, despite the increasing cultivation of popcorn. The objective of this trial was to determine whether agricultural traits and popping expansion from hybrid IAC 125 could be affected by plant density and levels of irrigation water, in addition to determining the significance level of the interaction between both factors. We investigated five plant populations (40,000, 55,000, 70,000, 85,000, and 100,000 plants ha-1) and five different levels of water depth in 2014/2015 [574.86 (without supplementary irrigation), 609.86, 644.86, 679.86 (control), and 714.86 mm] and 2015/2016 [857.4 (without supplementary irrigation), 867.26, 886.60, 916.78 (control), and 959.81 mm] using a complete block design with split-plot, comprising a main plot (for plant populations) and subplot (for water depth), with six replicates for each set. We found increasing linear effects from grain yield under population density and levels of water depth, but this interaction was not significant. Moreover, the popping expansion for the main effects and the interaction between plant populations and water depth, were not significant.

Limitations of cuttings become an essential problem in the expansion of cassava plantations. One strategy that can be taken is to reduce the length of the cuttings and increase the plant population to increase the area planted and produce more stems per unit area for the next growing season. This study aimed to determine the effect of cutting length and plant population per hectare on the growth and production of cassava stems. The research was carried out at the Jambegede Agricultural Technology Research and Assessment Installation in February–December 2020. The treatment consisted of two factors, namely three levels of cutting length (2, 4, and 10 buds/cutting) and three levels of the population (10,000, 30,000, and 40,000 plants/ha). The experiment used the Malang-4 variety and was applied to a completely randomized split-plot experimental design of three groups with the population as the main plot and the number of buds as sub-plots. The results showed that the number of buds/cutting increased the number of growing plants, one and three-month plant height, the number of viable stems, the length of unfit stems for seedlings, and decreased the percentage of dead plants. On the other hand, plant population/ha increases the percentage of dead plants, stem length unsuitable for seeds, and number of stems suitable for seeds. The interaction between the number of buds/cutting and the population was seen in the diameter of the three-month-old stems, the number of stems unsuitable for seedlings, the number of plants grown, the number of dead plants, and the number of plants harvested. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the agronomic performance of sorghum grown in different combinations of row spacing and plant density, as well as possible interferences on silage quality. No other study dedicated to identifying the interference of plant spatial arrangement on the cultivation of silage material has been developed in the productive context of the Amazon Biome, making it necessary to understand the behavior of the studied factors. The treatments were arranged in a split-plot scheme: the plots corresponded to three row spacings (0.45 m, 0.60 m, and 0.75 m) and subplots at four densities (105,000, 120,000, 135,000, and 150,000 plants ha−1). The agronomic and productivity characteristics of sorghum and the fermentative and bromatological characteristics of forage and silage were evaluated. The sorghum plants showed an increase in plant height and green and dry mass yield when using higher densities (p < 0.05). For the culm diameter variable, an isolated effect of the factors was observed, with reduced diameter when grown closer to inter-row spacing or using higher plant densities. No effect of the factors was found (p > 0.05) for morphological plant components. In silage, wider spacing promoted higher dry matter content. Regarding crude protein in the silage, higher percentages were obtained at closer spacing and higher plant density. The sorghum growing in dense conditions is indicated, given the positive performance in productivity and bromatological composition.

The effect of agronomic factors on the amount of water consumption and its productivity in arid and semiarid regions is very important. This study was conducted to diagnose agronomical procedures for increasing the yield and water productivity of sugar beet in two years (2016 and 2017). The experimental factors were: sowing date (spring and summer), planting arrangement (25-50 cm and 40-50 cm, double rows with a distance of 25 cm or 40 cm and a distance between each double row of 50 cm), and plant density (90, 120 and 160 thousand plant/ha). In the second year, the harvesting date, which consisted of conventional (October) and delayed (November), was added to the experiment. High temperature during and immediately after planting decreased emergence on the summer sowing date. The uniformity of roots and irrigation water productivity (WPirrig) in spring crops was higher than those of summer crops; meanwhile, on the summer sowing date, water consumption declined by 27% (and the sugar yield decreased intensively by 44%). Furthermore, planting arrangements of 25-50 resulted in better plant establishment and eventually increased the number of final plants. Besides, increasing plant density improved the uniformity of plants root. Sowing in summer compared to spring reduced root and sugar yield on a conventional harvesting date by about 40%. After 25 days' delay in harvesting time on both sowing dates (by mean), root yield, sugar yield, and WPirrig, increased by about 14, 28 and 22%, respectively. In general, at moderate densities (about 120 000), planting arrangement 40-50 and at low densities (less than 90 000, which usually occurs on the summer sowing date), planting arrangement 25-50 is recommended to increase yield and WPirrig.

Abstract Background Soil microbiome is an important part of the forest ecosystem and participates in forest ecological restoration and reconstruction. Niche differentiation with respect to resources is a prominent hypothesis to account for the maintenance of species diversity in forest ecosystems. Resource-based niche differentiation has driven ecological specialization. Plants influence soil microbial diversity and distribution by affecting the soil environment. However, with the change in plant population type, whether the distribution of soil microbes is random or follows an ecologically specialized manner remains to be further studied. We characterized the soil microbiome (bacteria and fungi) in different plant populations to assess the effects of phytophysiognomy on the distribution patterns of soil microbial communities in a temperate forest in China. Results Our results showed that the distribution of most soil microbes in different types of plant populations is not random but specialized in these temperate forests. The distribution patterns of bacteria and fungi were related to the composition of plant communities. Fungal species (32%) showed higher specialization than bacterial species (15%) for different types of plant populations. Light was the main driving factor of the fungal community, and soil physicochemical factors were the main driving factor of the bacterial community. Conclusion These findings suggest that ecological specialization is important in maintaining local diversity in soil microbial communities in this forest. Fungi are more specialized than bacteria in the face of changes in plant population types. Changes in plant community composition could have important effects on soil microbial communities by potentially influencing the stability and stress resistance of forest ecosystems.

ABSTRACT The aim of this study was to assess yield components and grain yield of soybean cultivars in response to sowing densities. For this, two soybean cultivars and five sowing densities were tested, in a two-factor scheme. The following yield components were measured by the end of the cycle: plant height; insertion height of the first pod; number of nodes per plant; number of pods with one, two, three and four grains; number of pods per plant; number of grains per plant; weight of a thousand grains; humidity and grain yield. Sowing densities did not cause significant variations of grain yield (bags ha-1) for any cultivar, however, higher populational densities promoted a reduction in the number of pods with two and three grains, as well as a reduction in the total number of pods and grains per plant for both cultivars. Cultivar NS 5700 IPRO was the most productive, with a higher number of pods with two and three grains and number of pods and grains per plant.

The biogas supply chain requires a correct combination of crops to maximize the methane yield per hectare. Field trials were carried out in North Italy over three growing seasons, according to a factorial combination of four cropping systems (maize as a sole-crop or after hybrid barley, triticale and wheat) and two maize plant densities (standard, 7.5 plants m−2 and high, 10 plants m−2) with the plants harvested as whole-crop silage. The specific methane production per ton was measured through the biochemical methane potential (BMP) method, while the methane yield per hectare was calculated on the basis of the BMP results and considering the biomass yield. The average methane yield of wheat resulted to be equal to 4550 Nm3 ha−1, and +17% and +28% higher than triticale and barley, respectively, according to the biomass yield. A delay in maize sowing reduced the yield potential of this crop; the biomass of maize grown after barley, triticale and wheat was 20%, 33% and 47% lower, respectively, than maize cultivated as a single crop. The high plant population increased the biomass yield in the sole-crop maize (+23%) and in the maize grown after barley (+20%), compared to the standard density. The highest biomass (32 t ha−1 DM) and methane yield (9971 Nm3 ha−1) within the cropping systems were obtained for barley followed by maize at a high plant density. This cropping system increased the methane yield by 46% and 18%, respectively, compared to the sole-crop maize or maize after triticale at a standard density. The smaller amount of available solar radiation, resulting from the later sowing of maize, reduced the advantage related to the application of a high plant density. [ABSTRACT FROM AUTHOR]

Tef is a small-seeded staple crop endemic to Ethiopia. However, its yield is low, constrained partly due to improper agronomic practices and lodging. Thus, during the 2019-2020 cropping season, a field experiment was carried out at Reef Tokko Taanne Hamilee in Hababo Guduru district, Western Ethiopia to examine the effects of seed rate and inter-row spacing on growth, phenology, yield, and lodging severity of tef crop. Three levels of seed rates (10, 15, and 20 kg ha-1) and three styles of row spacing (10, 15, and 20 cm) were combined in a factorial combination in a randomized block design with three replications.Tef variety called 'Guduru' was used as planting material. The result showed that seed rate and inter-row spacing had significant (p < 0.01) effects on all phenological and yield-related characteristics studied. Moreover, days to heading, days to maturity, grain yield and harvest index were significantly affected by the interaction effects of both seed rate and interrow spacing. Higher days to heading (68 days) and days to maturity (127 days) were recorded at a seeding rate of 20 kg ha-1 and10 cm inter-row spacing. Tef variety (Guduru) was taller (127.2 cm) under 10 kg ha-1 seed rate as compared to a higher seed rate of 20 kg ha-1 (120.8 cm). The highest dry biomass yield (51.3 kg plot-1) was obtained from a seeding rate of 20 kg ha-1 in combination with 20 cm inter-row spacing. Besides this, the maximum mean grain yield (19.8 kg plot-1) was recorded from 20 kg ha-1 seed rate and 15 cm inter-row spacing to achieve a higher yield in the study area. Furthermore, the highest straw yield (35.99 kg plot-1) was produced from the highest seed rate of 20 kg ha-1, whereas the smallest inter-row spacing (10 cm) produced the highest straw yield (33.5 kg plot-1). The maximum harvest index (56.1%) was obtained from 20 kg ha-1 seed rate and 15 cm inter-row spacing, a similar treatment combination as in the case of grain yield. 10 kg ha-1 seed rate and 20 cm inter-row spacing showed lowest lodging severity (24.1%) and (32.3%), respectively. The result suggests that sowing of tef at 20 kg ha-1 seed rate combined with 10 cm inter-row spacing which resulted in higher grain yield, straw yield and harvest index, could be recommended in the study area to achieve higher tef production. [ABSTRACT FROM AUTHOR]

Population size is a crucial parameter for both ecological research and conservation planning. When individuals are aggregated, estimating the size of a population through sampling raises methodological challenges, as the high variance between sampling units leads to imprecise estimates. Choosing the right sample design depending on the population aggregation level could improve the precision of estimates; however, this is difficult because studies comparing sample designs for aggregated populations have been limited to a few populations and sampling designs, so their results cannot be generalised.To address this gap, we combined simulations of spatial point populations and field counts of three plant species to compare the relative precision of estimates between three sampling methods: simple random sampling (SRS), systematic sampling (SYS) and spatially balanced sampling (SBS). Comparisons were performed on density and aggregation gradients for a range of sample sizes.Our simulations showed that SYS and SBS were always more precise than SRS when individuals were aggregated, reducing sampling variance up to 80% and 60%. The highest precision for estimating population size was always obtained when the average distance between sampling units equalled the diameter of the clusters (i.e. the groups of individuals). The difference in precision was similar for the natural populations, with sampling variance lowered by up to 75% (SYS) and 60% (SBS) compared to SRS.These findings lead us to recommend using SYS or SBS rather than SRS to estimate population size when individuals are spatially aggregated, as these consistently provide more precise estimates. Assessing cluster diameters in the field enables a quick assessment of the potential gain in precision to expect, and thus the best choice of sampling method depending on the trade‐off between precision and field constraints. [ABSTRACT FROM AUTHOR]

Tomato is an important field crop, and nutritional imbalances frequently reduce its yield. Diagnosis and Recommendation Integrated System (DRIS), uses ratios for nutrient deficiency diagnosis instead of absolute concentration in plant tests. In this study, local DRIS norms for the field tomatoes were established and the nutrient(s) limiting tomatoes yield were determined. Tomato leaves were analyzed for nutrients, to identify nutritional status using the DRIS approach. One hundred tomatoes fields were selected from Chatter Plain Khyber Pakhtunkhwa and the Sheikupura Punjab Pakistan. The first fully matured leaf was sampled, rinsed, dried and ground for analyzing P, K, Ca, Mg, Cu, Fe, Mn and Zn using an Inductively Coupled Plasma Atomic Emission Spectrophotometer (ICP AES). Plant tissue N and S were measured by the combustion method. The tomatoes yields were recorded at each location. The data were divided into high-yielding (≥3.79 kg/10 plant) and low-yielding (<3.79 kg/10 plant) populations and norms were computed using standard DRIS procedures. High-yielding plant population had a statistically greater mean S and Fe than the low-yielding population. The average balance index, the sum of functions, for S and Fe were -11.04 and -5.17 which reflected deficiency of S and Fe. Plant nutrients norms established may optimize plant nutrition in field tomatoes for high yield. [ABSTRACT FROM AUTHOR]

Plant population of 40,000 ha−1 with the respective inter- and intra-row spacing of 50 cm × 50 cm is the blanket recommendation for the production of head cabbage in Ethiopia. However, producers complain that this spacing produces too large head size, which is not the market's preference for household consumption instead for hotels and big institutions like universities. This two-season field experiment was conducted to optimize the head cabbage yield with appropriate head size by adjusting inter- and intra-row spacing. The result of the combined analysis over location and season revealed that all tested parameters were significantly (P < 0.05) influenced by the interaction effect of inter- and intra-row spacing. The combinations of 35 cm × 30 cm, 35 cm × 50 cm, and 50 cm × 30 cm inter- and intra-row spacing gave the highest head yield of 45, 43 significantly, and 42 t ha−1, respectively as compared to other treatment combinations. The interaction of the lowest inter- and intra-row spacing of 35 cm × 30 cm gave the lowest average head weight of 923 g of cabbage. The result showed that as intra-row spacing increased from 30 to 50 cm with all possible combinations of inter-row spacing, head-sized cabbage increased linearly. The current study identified that blanket recommendation of 50 cm × 50 cm inter-and intra-row spacing which assures a plant population of 40,000 ha−1 produced more than 1.4 kg individual head weight with a yield penalty of 10.70 t ha−1 compared to 50 cm × 30 cm inter- and intra-row spacing combination which assures a plant population of 66,667 ha−1. The current study confirmed that the earlier blanket recommendation of 40,000 plants ha−1 should be enhanced to a plant population of 66,667 ha−1 with a yield advantage of 131%. Concretely the manifested plant population difference gives an opportunity to producers to harvest a maximum yield with an acceptable head size of 1.2 kg. Therefore, it is concluded that the combination of 50 cm × 30 cm inter- and intra-row spacing assures that a plant population of 66,667 ha−1 is optimum for the production of head cabbage in the study and similar agro-ecologies.

In Yakutia, natural floodplain meadows and steppes have long been involved in economic activities. To develop methods of rational use, one needs to constantly consider the state of vegetation, mainly its constituent populations. Our research focuses on studying the dynamics of the vitality of the populations of the Agrostis diluta Kurcz. and steppe Psathyrostachys caespitosa (Sukaczev) Peschkova cereals. These species play an essential role in the composition of vegetation cover. We determined the vitality coefficient IVC. Our study of populations over several years has revealed the dynamic mobility of the vital structure, which is of adaptive significance and ensures the sustainability of populations. We have found that the vital structure of the cereal populations of the meadow Agrostis diluta and the steppe Psathyrostachys caespitosa during long-term studies (2007–2013 and 2007–2016, respectively) is heterogeneous. In unfavorable humidification conditions, we characterize years as depressive. Under favorable conditions of humidification, they quickly turn into thriving plants. In addition to the weather of the vegetation periods, habitat specificity affects the vitality of species populations that differ in ecological and coenotic characteristics. The Q quality index and IVC correspond to each other by year and form a clear descending order during the transition from a thriving to a depressive state. Currently, the vital state of the populations of both species is satisfactory.

Although there is adequate information on the influence of plant population on root yield and size of carrot on flat and raised bed for rain fed production system, information on ridge-furrow bed preparation method is limited for irrigation production system. Therefore, in this study, field experiments were conducted for 2 years to determine the appropriate spacing of carrot on ridge-furrow carrot production practice under irrigation. Root yield increased significantly as the population increased. On the contrary, root size significantly decreased as population increased. The result of combined analysis over season and locations indicated that the narrowest spacing of 10 cm × 4 cm rows on the ridge and between plants, respectively, which accommodates 1,250,000 plants ha−1 gave significantly highest marketable carrot root yield of 26 t ha−1 followed by 22.6 t ha−1 with spacing of 20 cm × 4 cm which accommodates 1,000,000 plants ha−1, but it produced the smallest individual root weight of 83 g which is mostly preferred for household consumption unlike jumbo roots. Therefore, in terms of root sizes and marketable yield, the current study identified that spacing of 10 cm × 4 cm is optimum on ridge-furrow carrot production practices.

Current trends in agriculture dictate an urgent need for the reduction of input resources while maintaining high biomass yield of good quality. The overall aim of the study was to investigate the interactive effects of planting density and water availability on growth, development, total biomass yield and quality of jute mallow. It was hypothesized that up to 20% of the crop irrigation water requirement could be saved through deficit irrigation without compromising biomass production and nutritional value. To achieve the stated aim, three planting densities: low (100 000 plants.ha−1); medium (167 000 plants.ha−1); and high (330 000 plants.ha−1) were tested in a two-year field trial. Each of these planting densities received three irrigation strategies: full irrigation (irrigation to field capacity (FC)); medium stressed (irrigation to 80% plant available water (PAW)); and stressed (irrigation to 60% PAW). All treatments were replicated three times in a randomized complete block design layout. Irrigation was applied every fifth day for all treatments under nitrogen non-limiting conditions. Results showed that high leaf area index (LAI), stomatal conductance (gs), total fresh yield, and mineral content (Zn and K) were attained at the medium planting density of 167 000 plants.ha−1 under the medium stress (irrigation to 80% PAW) strategy. Consequently, 20% less than is needed to fill the root zone to FC was saved. Hence, the hypothesis was accepted. On the other hand, the irrigation strategy of irrigation to FC increased the length and dry mass of the roots.

In this paper, a mathematical model is applied to investigate the effect of density of allelochemicals on plant population involving delay. The model is constructed using a system of nonlinear delay differential equations. In the model, there are three state variables: plant populations (P1 & P2) and density of allelochemical (T). It is assumed that in the presence of density of allelochemicals, plant populations are affected. It further delays the conversion of resource into the density of allelochemicals and hence affects the plant population adversely. This effect is observed by using delay in the competition model. Equilibrium points are calculated. Using the Routh–Hurwitz theorem, certain explicit formulations defining the stability and path of the Hopf‐bifurcation periodic solutions at the positive equilibrium are obtained. Further, the direction of these bifurcating periodic solutions is also studied. Numerical simulation and graphical support are provided for analytical findings using MATLAB. [ABSTRACT FROM AUTHOR]

ABSTRACT Increases in plant density associated with the use of plant growth regulators, aside from modifying the plant architecture, can also change the maize yield performance. This study aims to investigate the yield components and grain yield of maize hybrids with contrasting leaf architecture, in response to different plant populations and trinexapac-ethyl rates (TE). Field experiments were conducted in two growing seasons, in a (5 x 5) factorial randomized block design. The treatments consisted of: five plant population (40, 60, 80, 100, and 120 thousand plants ha-1) and five TE rates (0, 100, 200, 300, and 400 g a.i. ha-1), with four replications, using the hybrids 2B710 HX and Status TL. We evaluated the number of rows per ear, ear length, number of grains per row, 1000-grain mass, and yield. An increased plant density reduces ear length, number of grains per row and 1000-grain mass, without changing the number of grain rows per ear. TE rates increases ear length and number of grains per row and reduces 1000-grain mass, mainly under favorable cultivation conditions. TE interacts with the plant density, changing the maize yield components with increases in grain yield, but these gains variy, according to the environment and genotype characteristics.

Background: Soil microbiome is an important part of the forest ecosystem and participates in forest ecological restoration and reconstruction. Niche differentiation with respect to resources is a prominent hypothesis to account for the maintenance of species diversity in forest ecosystems. Resource-based niche differentiation has driven ecological specialization. Plants influence soil microbial diversity and distribution by affecting the soil environment. However, with the change in plant population type, whether the distribution of soil microbes is random or follows an ecologically specialized manner remains to be further studied. We characterized the soil microbiome (bacteria and fungi) in different plant populations to assess the effects of phytophysiognomy on the distribution patterns of soil microbial communities in a temperate forest in China. Results: Our results showed that the distribution of most soil microbes in different types of plant populations is not random but specialized in these temperate forests. The distribution patterns of bacteria and fungi were related to the composition of plant communities. Fungal species (32%) showed higher specialization than bacterial species (15%) for different types of plant populations. Light was the main driving factor of the fungal community, and soil physicochemical factors were the main driving factor of the bacterial community. Conclusion: These findings suggest that ecological specialization is important in maintaining local diversity in soil microbial communities in this forest. Fungi are more specialized than bacteria in the face of changes in plant population types. Changes in plant community composition could have important effects on soil microbial communities by potentially influencing the stability and stress resistance of forest ecosystems. [ABSTRACT FROM AUTHOR]

The objectives of this study was to investigate yield, nutrient concentration and uptake of fluted pumpkin (Telfairia occidentalis Hook. F.) in response to plant densities and fertilizer application. Two fluted pumpkin plant densities (10,000 and 20,000 plants ha-1) D1 and D2 were evaluated at three levels of NPK fertilizer (F1, 20 t ha-1 poultry manure, F2, 300 kg ha-1 NPK 15:15:15 and F3, 10 t ha-1 poultry manure + 150 kg ha-1 NPK 15:15:15) using a factorial arrangement in randomized complete block design (RCBD) with three replications. Leaf length, breadth, number of leaves and stem diameter were significantly increased at both plant densities of 10,000 and 20,000 plants ha -1 while herbage yield increased with higher plant density of 20,000 plants ha-1using 300 kg ha-1 inorganic NPK 15:15:15 or a combination of 10 t ha-1 poultry manure + 150 kg ha-1 inorganic NPK 15:15:15. Potassium (K) concentration was significantly (p < 0.05) higher at 10,000 plants ha-1 and Iron (Fe) uptake was higher with combine application of organic and inorganic fertilizer (F3). To maximize good herbage yield of fluted pumpkin, farmers in this locality should adopt plant density of 20,000 plants ha-1using 300 kg ha-1 inorganic NPK 15:15:15 (D2F2) or a combination of 10 t ha-1 poultry manure + 150 kg ha-1 inorganic NPK 15:15:15 (D2F3). [ABSTRACT FROM AUTHOR]

The effect of agronomic factors on the amount of water consumption and its productivity in arid and semiarid regions is very important. This study was conducted to diagnose agronomical procedures for increasing the yield and water productivity of sugar beet in two years (2016 and 2017). The experimental factors were: sowing date (spring and summer), planting arrangement (25-50 cm and 40-50 cm, double rows with a distance of 25 cm or 40 cm and a distance between each double row of 50 cm), and plant density (90, 120 and 160 thousand plant/ha). In the second year, the harvesting date, which consisted of conventional (October) and delayed (November), was added to the experiment. High temperature during and immediately after planting decreased emergence on the summer sowing date. The uniformity of roots and irrigation water productivity (WPirrig) in spring crops was higher than those of summer crops; meanwhile, on the summer sowing date, water consumption declined by 27% (and the sugar yield decreased intensively by 44%). Furthermore, planting arrangements of 25-50 resulted in better plant establishment and eventually increased the number of final plants. Besides, increasing plant density improved the uniformity of plants root. Sowing in summer compared to spring reduced root and sugar yield on a conventional harvesting date by about 40%. After 25 days' delay in harvesting time on both sowing dates (by mean), root yield, sugar yield, and WPirrig, increased by about 14, 28 and 22%, respectively. In general, at moderate densities (about 120 000), planting arrangement 40-50 and at low densities (less than 90 000, which usually occurs on the summer sowing date), planting arrangement 25-50 is recommended to increase yield and WPirrig. [ABSTRACT FROM AUTHOR]

Row crops normally grown in Southeast USA are cotton (Gossypium hirsutum L.), corn (Zea mays L.), and peanut (Arachis hypogea L.) with a focus on the higher economic value for peanut. Peanut is typically planted using a twin-row pattern and purchasing a twin-row planter may not be cost effective unless used with other rotational crops. The objectives were to compare corn yield when planted in twin-rows, with two plant densities, at multiple locations, and irrigated with drip or sprinkler system. Corn was planted in single and twin-row patterns at 7.9 seeds/m (normal; 86,100 seeds/ha) and 4.9 seeds/m (half-normal; 53,600 seeds/ha) at multiple locations and cropping seasons. Irrigation systems consisted of subsurface drip (SSDI), shallow subsurface drip (S3DI) and overhead sprinkler. Single and twin-row with normal seeding rate had same yield across years, locations, or irrigation system 88% of the time. With drip irrigation only, twin-row half-normal seeding rate had the same yield as the single-row normal seeding rate 75% of the time and when factoring in seed savings had an economic benefit of $56/ha. The single-row half-normal seeding rate always had lower yield compared with other treatments. The S3DI irrigation system had greater yield than SSDI for both row patterns and seeding rates. Therefore, a twin-row planter purchased for peanut may be used to plant corn without yield reduction using normal seeding rates under either drip or sprinkler irrigation systems. [ABSTRACT FROM AUTHOR]

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The aim of this study was to assess yield components and grain yield of soybean cultivars in response to sowing densities. For this, two soybean cultivars and five sowing densities were tested, in a two-factor scheme. The following yield components were measured by the end of the cycle: plant height; insertion height of the first pod; number of nodes per plant; number of pods with one, two, three and four grains; number of pods per plant; number of grains per plant; weight of a thousand grains; humidity and grain yield. Sowing densities did not cause significant variations of grain yield (bags ha-1) for any cultivar, however, higher populational densities promoted a reduction in the number of pods with two and three grains, as well as a reduction in the total number of pods and grains per plant for both cultivars. Cultivar NS 5700 IPRO was the most productive, with a higher number of pods with two and three grains and number of pods and grains per plant. [ABSTRACT FROM AUTHOR]

The objectives of this study was to investigate yield, nutrient concentration and uptake of fluted pumpkin (Telfairia occidentalis Hook. F.) in response to plant densities and fertilizer application. Two fluted pumpkin plant densities (10,000 and 20,000 plants ha-1) D1 and D2 were evaluated at three levels of NPK fertilizer (F1, 20 t ha-1 poultry manure, F2, 300 kg ha-1 NPK 15:15:15 and F3, 10 t ha-1 poultry manure + 150 kg ha-1 NPK 15:15:15) using a factorial arrangement in randomized complete block design (RCBD) with three replications. Leaf length, breadth, number of leaves and stem diameter were significantly increased at both plant densities of 10,000 and 20,000 plants ha -1 while herbage yield increased with higher plant density of 20,000 plants ha -1using 300 kg ha-1 inorganic NPK 15:15:15 or a combination of 10 t ha-1 poultry manure + 150 kg ha-1 inorganic NPK 15:15:15. Potassium (K) concentration was significantly (p < 0.05) higher at 10,000 plants ha -1 and Iron (Fe) uptake was higher with combine application of organic and inorganic fertilizer (F3). To maximize good herbage yield of fluted pumpkin, farmers in this locality should adopt plant density of 20,000 plants ha -1using 300 kg ha-1 inorganic NPK 15:15:15 (D2F2) or a combination of 10 t ha-1 poultry manure + 150 kg ha-1 inorganic NPK 15:15:15 (D2F3).

Carrots (Daucus carota L. var sativus) in the midwestern United States are generally raised commercially on sandy-loam or muck soils. Some smaller growers may not have the luxury of an ideal soil type, so raised beds are often recommended to improve taproot growth. To determine specific yield and shape responses of carrots to raised-bed culture in heavy soil, three hybrids (‘Cupar’, ‘Envy’, and ‘Naval’) were grown in 2019 and 2020 on raised or flat beds in clay-loam soil. In addition, two seeding rates (high or low) were incorporated into the split-split plot design. ‘Cupar’ was larger and less misshapen than the other hybrids, but total marketable yields were similar among all three. ‘Naval’ was the most cylindrical. High seeding rate generally resulted in more numerous but smaller marketable roots and no change in total marketable weight. Raised beds caused a 10.6% increase in total marketable weight by allowing more marketable roots classified as “short” (between 76 and 127 mm long, diameter >25 mm) to grow to lengths more than 127 mm long. The average taproot cylindricity was increased and diameter decreased by growing on raised beds. Soil penetration resistance at 7.6 cm was correlated with many of the measured responses.

Introduction: Environmental stress is both a major force of natural selection and a prime factor affecting crop qualities and yields. The impact of the GRAS [gibberellic acid-insensitive (GAI), repressor of GA1–3 mutant (RGA), and scarecrow (SCR)] family on plant development and the potential to resist environmental stress needs much emphasis. Objectives: This study aims to investigate the evolution, expansion, and adaptive mechanisms of GRASs of important representative plants during polyploidization. Methods: We explored the evolutionary characteristics of GRASs in 15 representative plant species by systematic biological analysis of the genome, transcriptome, metabolite, protein complex map and phenotype. Results: The GRAS family was systematically identified from 15 representative plant species of scientific and agricultural importance. The detection of gene duplication types of GRASs in all species showed that the widespread expansion of GRASs in these species was mainly contributed by polyploidization events. Evolutionary analysis reveals that most species experience independent genome-wide duplication (WGD) events and that interspecies GRAS functions may be broadly conserved. Polyploidy-related Chenopodium quinoa GRASs (CqGRASs) and Arabidopsis thaliana GRASs (AtGRASs) formed robust networks with flavonoid pathways by crosstalk with auxin and photosynthetic pathways. Furthermore, Arabidopsis thaliana population transcriptomes and the 1000 Plants (OneKP) project confirmed that GRASs are components of flavonoid biosynthesis, which enables plants to adapt to the environment by promoting flavonoid accumulation. More importantly, the GRASs of important species that may potentially improve important agronomic traits were mapped through TAIR and RARGE-II publicly available phenotypic data. Determining protein interactions and target genes contributes to determining GRAS functions. Conclusion: The results of this study suggest that polyploidy-related GRASs in multiple species may be a target for improving plant growth, development, and environmental adaptation.

Reducing the leaf senescence rate could improve the grain yield in maize. In the present study, maize seeds were treated with uniconazole at concentrations of 0 and 25 mg kg-1, and nitrogen was applied at 0, 150, and 225 kg ha-1 to maize crop planted at a density of 105,000 plants ha-1. Applying uniconazole and nitrogen reduced the leaf senescence rate by increasing the leaf area per plant, chlorophyll content, net photosynthetic rate, stomatal conductance, and transpiration rate. Uniconazole and nitrogen increased the electron transport rate, photochemical quenching coefficient, variable fluorescence, maximal quantum yield of PSII photochemistry, and effective quantum yield of PSII photochemistry. Uniconazole and nitrogen reduced the intercellular carbon dioxide concentration, nonphotochemical quenching coefficient, and malondialdehyde content but increased the soluble protein content and antioxidant enzyme activities. Applying uniconazole at a concentration of 25 mg kg-1 and nitrogen at a rate of 150 kg ha-1 obtained the maximum grain yield in maize.

Ocimum basilicum L., or sweet basil, is a valuable aromatic and medicinal plant that is used in aromatherapy to energize, relax, and stimulate the mind. It is also used in the pharmaceutical industry for its anti-ageing and therapeutic qualities. Farmers who depend only on conventional food crops run the danger of crop failure as a result of unanticipated circumstances like uncertain weather, pest outbreaks, or disease epidemics. In contrast, intercropping offers a kind of insurance against total crop loss by diversifying farm outputs. The present study aims to increase field productivity and efficient use of land resources under sweet basil-based inter-cropping systems. In the experiment, 17 different treatments (12 treatments comprising of inter-cropping of sweet basil (55,555 plants/ha plant population) with four conventional crops namely maize (Zea mays L.), pearlmillet (Pennisetum glaucum L.), pigeonpea (Cajanus cajan L.) and okra (Abelmoschus esculentus L.) at three plant populations, i.e., 100% (55,555 plants/ha), 75% (37,037 plants/ha), and 50% (27,777 plants/ha). Also, all five sole crops (4 conventional crops and sweet basil) were planted. The study findings showed that the maximum fresh herb yield of sole sweet basil culture at 100% plant population (14.2 t/ha with 0.70% oil content and 99.2 kg/ha oil yield) was almost equal to that of co-cultivation of sweet basil with pigeonpea at 50% plant population (14 t/ha with 0.70% oil content and 98.2 kg/ha oil yield). Similarly, LER varied from 1.50 to 1.90 and the ATER varied from 1.32 to 1.82. The inter-cropping system based on sweet basil is an advantageous strategy to maximize resource use efficiency. Nevertheless, net returns of sweet basil were found to be maximum with pigeon pea (1762–1881 USD/ha) followed by okra (1507–1638 USD/ha), maize (1042–1310 USD/ha) and pearl millet (809–1029 USD/ha). Moreover, for better herb yield and net returns, it was more profitable for the farmers to co-cultivate sweet basil with pigeon pea at 50% plant population. • Improved resource use in rainfed areas through intercropping for sustainable agriculture. • Herb, oil yield and quality increases in sweet basil with pigeon pea at 50% (27,777 plant/ha) plant population. • The LER ranged from 1.50 to 1.90, and ATER ranged from 1.32 to 1.82. • Legume crop- pigeon pea, positively influences sweet basil and improves RUE. [ABSTRACT FROM AUTHOR]

Weeds are a major constraint to quinoa production since no herbicide tolerant variety is available worldwide. This raises the importance of cultural practices for controlling weeds. Optimizing plant spacing and implementing effective weeding practices may help to enhance quinoa productivity and profitability. The objective of current study was to utilize the plant spacing as an alternate option for ensuring effective weed management and profitable quinoa production for the irrigated plains. The effect of planting spacing on weed flora in quinoa was evaluated for two consecutive years (2021–22 and 2022–23). Two weeding regimes (weedy and weed-free) along with three plant spacings viz., 10, 20, and 30 cm were tested using a randomized complete block design in split-plot arrangement with three replications. In the weedy plots, no weeding was done, while in the weed-free plots, manual weeding was performed to keep them weed-free throughout the growing season. Different plant spacing significantly influenced weed biomass and density in quinoa. Narrow spaced plants (10 cm) gave maximum weed suppression as against widely spaced plants (30 cm) and a concomitant yield increase. Medium plant spacing (20 cm) gave maximum grain yield by attaining the optimum plant population under weed-free conditions during both years. Economic analysis also revealed that medium plant spacing with weed-free conditions was beneficial compared to other treatments regarding gross returns, net returns, and benefit-cost ratio. This study highlights that quinoa spacing primarily determined quinoa-weed competition and can be a tool for weed management in this crop. • Weed growth and quinoa yield response to plant spacing and weeding regimes. • Presence of weeds caused biotic stress and led to a severe decline in crop yield. • Narrow plant spacing: better weed control and grain yield under weedy conditions. • Medium plant spacing resulted in higher grain yield under weed-free treatment. • Findings can be used for designing quinoa's integrated weed management package. [ABSTRACT FROM AUTHOR]

Occupancy models have been underused in multispecies plant studies. We evaluated the effectiveness of occupancy models to document impacts of management on grassland plant species populations in a pilot study. The study was designed to answer three questions: (1) From a list of 44 plant species, how many will have sufficient frequency to be analyzed? (2) Within a single site, which factor (sampling year or unit) influences occupancy and detection of each plant species? (3) How does the number of plots and visits affect the number of species with sufficient frequency for analysis? In 2012 and 2013, occupancy and detection probabilities of 44 plant species were assessed using permanently marked plots on two different grassland sites. Within each site, a fire and grazing managed unit and a burn‐only control unit were used to test the efficacy of occupancy modeling for multiple plant species and study design. Four of the 44 species had sufficiently high known presence (π) on both sites and years to be analyzed. There was little evidence to support that occupancy was different between years, despite very different weather patterns. There was support that occupancy was different in the burned and grazed unit compared with the control for Rhus copallinum L. Detection was highest (≥0.8) for R. copallinum, while the other species analyzed varied. In 2012, eight species had sufficient π for analysis. In 2013, 12 species had sufficient π for analysis. Occupancy models can be useful for investigating multiple plant species; however, a priori investigation of species' distribution is necessary to ensure species can be analyzed. Detection of plants was never 1, and therefore, detection should continue to be incorporated in plant population models, regardless of modeling technique. [ABSTRACT FROM AUTHOR]

Potato (Solanum tuberosum) stem density variation in the field can be used to inform harvest timing to improve tuber size distribution. Current methods for quantifying stem density are manual with low throughput. This study examined the use of Unmanned Aerial Vehicle imagery as a high-throughput alternative. A colour-based feature extraction technique and a deep convolutional neural network (CNN) were compared for their effectiveness in enumerating apical meristems as a proxy to subtending stems. Two novel colour indices, named the cumulative blue differences index and blue difference normalized index, showed significant differences (P < 0.001) between meristematic leaves and mature leaves in comparison to other indices. The two indices were used to generate 500 pseudo-labelled human-corrected images as training data for the CNN. Benchmarked against a human labelled test dataset, the CNN performed better with a normalized Root Mean Square Error (nRMSE) of 0.09 than the sole use of the image analysis algorithm (nRMSE = 0.3) in predicting the number of meristems in a canopy at 52 days after planting. Furthermore, the CNN had better precision (Intersection over Union [IOU]: 0.49 and 0.56, respectively) than the image analysis algorithm (IOU: 0.33 and 0.13, respectively). Meristem counts in both approaches showed a linear relationship with actual subtending stem counts (P < 0.001). This study demonstrates the validity of using traditional image analysis and CNNs to generate meristem detectors with acceptable nRMSE. Transfer learning with CNN is proposed for developing meristem detectors for evaluating stem density variation from UAV images in the field. [ABSTRACT FROM AUTHOR]

Background: Peanut yields are affected by plant density and chemical controls. Methods: A field experiment was conducted in Southern China to investigate the effects of population density and paclobutrazol applications on the growth and yield of peanuts with monoseeding and double seeding patterns. Result: Paclobutrazol application could improve peanut yields. The highest peanut yields were observed with 250 mg L-1 paclobutrazol and a plant density of 235 410 plants ha-1, with the monoseeding pattern. Our results suggest that monoseeding and paclobutrazol could be applied to enhance peanut yields in Southern China. [ABSTRACT FROM AUTHOR]